Difference Between 2 JavaScript Arrays

arrayDiff.js

Array.prototype.diff = function (a) {
    return this.filter(function (i) {
        return a.indexOf(i) === -1;
    });
};


// usage:
[1, 2, 3, 4, 5, 6].diff([2, 4, 6]);
// => [1, 3, 5]